CONSUMERS ENERGY CO

Incident Narrative

AT APPROXIMATELY 9:45 AM ON MARCH 15, 2014 NEAR WELL O-119 AT OVERISEL STORAGE FIELD IN HAMILTON, MI, A NEARBY PROPERTY OWNER REPORTED A SUSPECTED NATURAL GAS LEAK. CONSUMERS ENERGY'S GAS CONTROL WAS NOTIFIED AT 9:47 AM OF THE LEAK. CONSUMERS ENERGY CREWS ARRIVED ON SITE AND DISCOVERED A NATURAL GAS LEAK ON LATERAL #6, APPROXIMATELY 90 YARDS FROM WELL O-119. LATERAL #6 WAS ISOLATED BY CLOSING ALL VALVES AFFECTING GAS FLOW TO THE LATERAL. THE LATERAL WAS SUBSEQUENTLY BLOWN DOWN AND TAKEN OUT OF SERVICE. THE CONTROLLED BLOWDOWN WAS COMPLETED AT 3:20 PM ON MARCH 15. PRELIMINARY INCIDENT INVESTIGATION REVEALED A 7/32"" DIAMETER HOLE IN THE GIRTH WELD OF THE 10"" STEEL PIPE, APPARENTLY DUE TO INTERNAL CORROSION PITTING. THE LATERAL CURRENTLY REMAINS OUT OF SERVICE UNTIL INVESTIGATION AND REMEDIATION HAS BEEN COMPLETED. A TELEPHONIC REPORT WAS INITIALLY FILED WITH NRC DUE TO A POTENTIAL FOR GAS LOSSES IN EXCESS OF 3 MMCF (MILLION CUBIC FEET). EXPOSURE OF THE LEAK AND SUBSEQUENT CALCULATIONS DETERMINED THAT THE VOLUME OF GAS RELEASED WAS MUCH SMALLER; HOWEVER AN INCIDENT REPORT IS STILL BEING FILED DUE TO INCURRED COSTS IN EXCESS OF $50,000. NO FIRE DEPARTMENT, POLICE, BLOCKED TRAFFIC OR MEDIA PRESENCE WAS NOTED ON SITE AT THE TIME OF THE INCIDENT. THE DAMAGE SECTION OF THE PIPELINE WAS TRANSPORTED TO THE CONSUMERS ENERGY TRAIL STREET LABORATORY FOR FURTHER EXAMINATION. THE LABORATORY EVALUATION AND THE HISTORICAL EVIDENCE CONFIRMED THE LEAK WAS DUE TO EFFECTS OF INTERNAL CORROSION. IN ADDITION TO COMPREHENSIVE METALLURGICAL TESTING, CONSUMERS ENERGY CONTRACTED IN-LINE INSPECTION VENDOR, INLINE DEVICES TO INSPECT THE LATERAL AND SYSTEM INTEGRITY EMPLOYEES CONDUCTED A THOROUGH REVIEW OF THE FINDINGS; IDENTIFYING MULTIPLE DIG LOCATIONS TO VALIDATE TOOL DATA AND DEVELOP A REMEDIATION PLAN. SEVEN SECTIONS OF PIPE WERE REPLACED ( APPROXIMATELY 400') WHERE THE TOOL PREDICTED METAL LOSS IN OR NEAR THE GIRTH WELD. REMEDIATION WORK WAS COMPLETED AND THE LATERAL WAS PLACED BACK IN SERVICE ON JANUARY 16, 2015.